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Analog Devices Inc./Maxim Integrated MAX703CSA+T
- Part No.:
- MAX703CSA+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
MAX703CSA+T.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:4,271
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Product details
Overview
MAX703CSA+T from Maxim Integrated is a microprocessor supervisory circuit designed for power-supply monitoring and battery-backed RAM support in +5V μP systems. It provides active-low reset assertion at 4.65V VCC threshold, 200ms reset pulse width, battery switchover with 40mV hysteresis, and a 1.25V precision power-fail comparator input - all in an 8-pin SO package for embedded controllers and intelligent instruments.
For engineers reviewing the MAX703CSA+T datasheet, MAX703CSA+T pinout, MAX703CSA+T application, or MAX703CSA+T equivalent, key selection criteria include guaranteed RESET assertion down to VCC = 1V, 50nA quiescent current in battery-backup mode, TTL/CMOS-compatible manual reset input with internal 250µA pullup, and validated operation across 0°C to +70°C ambient temperature.
Technical Context
The MAX703CSA+T integrates four tightly coupled functions: a precision bandgap-based supply monitor with 4.65V reset threshold and 40mV hysteresis; a p-channel MOSFET-based battery switchover circuit with 5Ω (VCC→VOUT) and 80Ω (VBATT→VOUT) on-resistance paths; a 1.25V reference comparator for PFI/PFO power-fail signaling; and a debounced active-low manual reset input with 150ns minimum pulse width tolerance.
Its architecture ensures deterministic behavior during brownout: RESET remains asserted while VCC stays below 4.65V, and the internal timer restarts on each voltage dip, guaranteeing ≥140ms (typ. 200ms) low pulse after recovery. In battery-backup mode (VCC < VRST), internal circuitry powers from VBATT, PFI/PFO are disabled, and RESET is held low - enabling reliable CMOS RAM retention without external supervision.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 4.65V ±150mV - asserts active-low RESET when VCC drops below this level, ensuring μP initialization before logic corruption |
| Reset Pulse Width | 140–280ms - guarantees sufficient hold time for μP boot sequence after power recovery |
| Supply Current (Active) | 200–350µA - enables low-power system monitoring without burdening +5V rail |
| Battery-Backup Current | 50nA - minimizes lithium cell drain during extended backup operation |
| PFI Threshold | 1.25V ±50mV - supports precise power-fail warning or low-battery detection via external resistor divider |
| VOUT Switch Resistance | 5Ω (VCC path), 80Ω (VBATT path) - limits voltage drop under 5mA load, preserving RAM data integrity |
| Operating Temperature | 0°C to +70°C - qualified for commercial-grade embedded instrumentation and controller applications |
Pinout & Package
MAX703CSA+T is housed in an 8-pin SO (Small Outline) package with gull-wing leads, RoHS-compliant, and footprint compatible with JEDEC MS-012AA standard (land pattern 90-0096).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - VOUT | Switched Power Output | Delivers regulated +5V (from VCC) or backup battery voltage (from VBATT) to CMOS RAM; auto-switches on brownout |
| 2 - VCC | +5V Supply Input | Main system power input; monitored for reset generation and used as primary VOUT source above 4.65V |
| 3 - GND | Ground Reference | Common return for all internal circuits and external loads; required for accurate threshold sensing |
| 4 - PFI | Power-Fail Input | Analog comparator input referenced to 1.25V; triggers PFO low when voltage falls below threshold |
| 5 - PFO | Power-Fail Output | Open-drain output asserting low on PFI undervoltage; disabled during battery-backup mode |
| 6 - MR | Manual Reset Input | Active-low TTL/CMOS-compatible input with internal 250µA pullup; initiates 200ms reset pulse on button press |
| 7 - RESET | Reset Output | Active-low open-drain output asserted during power-up, brownout, or MR activation; guaranteed valid down to VCC = 1V |
| 8 - VBATT | Battery Backup Input | Accepts 2.8V–4.8V lithium or supercap backup source; enables automatic switchover when VCC fails |
Key Features
| Feature | Design Value |
|---|---|
| Guaranteed RESET Assertion to VCC = 1V | Ensures deterministic reset behavior even during deep brownout, preventing μP lockup when main supply collapses |
| 40mV Battery Switchover Hysteresis | Prevents oscillatory switching between VCC and VBATT during slow VCC decay, protecting RAM from voltage glitches |
| Debounced Manual Reset Input | Internal timing eliminates need for external RC debounce, simplifying pushbutton interface and reducing BOM count |
| 1.25V Precision Reference Comparator | Enables accurate power-fail warning or secondary supply monitoring without external reference IC |
| Lead(Pb)-Free Packaging (+ suffix) | Complies with RoHS Directive 2011/65/EU; marked with "+" symbol per ordering information |
Applications
| Industrial Controller Monitoring | Embedded Instrument Power Management |
|---|---|
Use Scenario: PLC I/O modules require reliable reset during AC line sags and maintain SRAM contents during brief outages. IC Role / Device Role / Timing Role: MAX703CSA+T monitors +5V rail, asserts RESET on brownout, and switches VOUT to lithium backup to preserve configuration registers. Use Value: Eliminates need for discrete reset generator + analog switch, reducing board area by >30% and enabling 10-year battery life in sealed enclosures. | Use Scenario: Portable multimeters use supercapacitor backup to retain calibration data and measurement history across battery swaps. IC Role / Device Role / Timing Role: MAX703CSA+T detects VCC dropout, disables PFI comparator, and routes supercap voltage to VOUT within 10µs of VCC falling below 4.65V. Use Value: Achieves <50nA standby current during backup, extending supercap hold-up time to >72 hours at 25°C. |
| Computer Peripheral Supervision | Critical μP Power Monitoring |
Use Scenario: USB-to-serial adapters must initialize cleanly after host port enumeration and survive transient bus voltage dips. IC Role / Device Role / Timing Role: MAX703CSA+T provides 200ms reset pulse synchronized to VCC ramp, ensuring UART firmware starts only after stable +5V is established. Use Value: Prevents spurious UART transmission errors during hot-plug events, eliminating field-reported "garbled data on first connect" issues. | Use Scenario: Medical infusion pump controllers mandate fail-safe reset during battery transition and power-fail warning for safe shutdown. IC Role / Device Role / Timing Role: MAX703CSA+T uses PFI to monitor unregulated DC input, asserts PFO interrupt 100ms before VCC collapse, then asserts RESET when VCC reaches 4.65V. Use Value: Enables deterministic 200ms grace period for saving therapy parameters and entering safe state before power loss. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX705CPA+ | No battery backup; fixed 4.65V reset; includes CE write-protect output | Suitable where RAM backup is handled externally or unnecessary; adds memory protection function | Select when system uses external battery management or requires hardware write protection for EEPROM/Flash |
| TPS3808G18DBVR | Adjustable reset threshold (1.22V–5.5V); 350ms min reset pulse; no battery switchover | Designed for flexible supply monitoring across multiple rails; lacks integrated backup switching | Choose for multi-voltage systems needing programmable thresholds, but requires separate backup solution |
Compared with MAX705CPA+, MAX703CSA+T provides integrated battery switchover but omits write-protect functionality; versus TPS3808G18DBVR, it offers fixed-precision 4.65V monitoring with proven low-current backup operation, making it optimal for cost-sensitive, single-rail +5V systems requiring long-term RAM retention.
Availability
MAX703CSA+T is available at Aetrix Electronics and suitable for industrial controllers, embedded instrumentation, computer peripherals, and critical μP power monitoring applications requiring stable component supply, long-lifecycle availability, and RoHS-compliant packaging.
Supply support for MAX703CSA+T includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Maxim Integrated (now part of Analog Devices) designs precision analog, mixed-signal, and power-management ICs for industrial, computing, and communications markets.
The MAX703 product line delivers low-cost, highly integrated supervisory circuits optimized for +5V microprocessor systems requiring reliable reset generation, battery-backed RAM support, and power-fail warning - with emphasis on simplicity, low quiescent current, and commercial-temperature robustness.
FAQ
What is the guaranteed reset assertion voltage range for MAX703CSA+T?
The MAX703CSA+T guarantees active-low RESET assertion down to VCC = 1V, with a nominal reset threshold of 4.65V (min 4.50V, max 4.75V). This ensures deterministic reset behavior during severe brownout conditions while maintaining compatibility with standard +5V logic families. The device continues to assert RESET as long as VCC remains below the threshold, and holds it for ≥140ms after VCC rises above the threshold.
Does MAX703CSA+T support lithium battery backup, and what is the maximum allowable VBATT voltage?
Yes, MAX703CSA+T supports lithium battery backup with a maximum allowable VBATT voltage of 4.80V, as specified in Table 2 of the datasheet. It automatically switches VOUT to VBATT when VCC falls below 4.65V and VBATT exceeds VCC by ≥20mV, using 40mV hysteresis to prevent chatter. The device draws only 50nA in battery-backup mode, enabling multi-year operation from a CR2032 cell.
How does the power-fail comparator (PFI/PFO) function in MAX703CSA+T?
The PFI input compares against an internal 1.25V reference; when PFI voltage drops below this threshold, PFO goes low to signal impending power failure. In MAX703CSA+T, this comparator is disabled during battery-backup mode (PFO forced low), and its input current is limited to ±25nA - enabling high-impedance monitoring of unregulated supplies via external resistive dividers without loading the source.
Can MAX703CSA+T be used without a backup battery, and how should VBATT be handled?
Yes, MAX703CSA+T can operate without a backup battery: ground the VBATT pin and connect VCC directly to VOUT externally to bypass the internal switch and eliminate voltage drop. Alternatively, use the MAX705–MAX708 series if battery backup is not required, as they omit the VBATT function entirely while retaining reset and power-fail features.
What is the manual reset (MR) input behavior and timing specification for MAX703CSA+T?
The MR input is an active-low, TTL/CMOS-compatible pin with an internal 250µA pullup current. Pulling MR below 0.8V generates a reset pulse with minimum width of 140ms (typ. 200ms). Its 150ns minimum pulse width tolerance and built-in debouncing eliminate external components, and the input remains functional across the full 0°C to +70°C operating range of MAX703CSA+T.
MAX703CSA+T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Programmable:
- Not Verified
- Type:
- Battery Backup Circuit
- Number of Voltages Monitored:
- 1
- Voltage - Threshold:
- 4.65V
- Output:
- Push-Pull, Totem Pole
- Reset:
- Active Low
- Reset Timeout:
- 140ms Minimum
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
MAX703CSA+T FAQ
1.How can I place an order for MAX703CSA+T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX703CSA+T on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for MAX703CSA+T reliable?
The price and inventory of MAX703CSA+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX703CSA+T is usually 5 days.
3.What payment methods are accepted for MAX703CSA+T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX703CSA+T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX703CSA+T?
MAX703CSA+T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX703CSA+T order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for MAX703CSA+T?
For technical support, including MAX703CSA+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX703CSA+T requirements.
6.How does Aetrix verify that MAX703CSA+T is sourced from the original manufacturer or authorized distributors?
All MAX703CSA+T products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that MAX703CSA+T meets industry standards.
7.What is the process for return or replacement of MAX703CSA+T?
All MAX703CSA+T units undergo pre-shipment inspection (PSI). If there is an issue with MAX703CSA+T, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The MAX703CSA+T part is unused and in its original packaging.
Return procedure for MAX703CSA+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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